(a) A colourless gas P was given off when dilute tetraoxosulphate (VI) acid was added to zinc salt Q. On bubbling the gas through lime water, a white precip...

Answer Details

(a) The colourless gas P turns lime water milky (white precipitate R), so P is carbon(IV) oxide, CO₂. A zinc salt that gives CO₂ with dilute acid is a trioxocarbonate(IV), so Q is zinc trioxocarbonate(IV), ZnCO₃, and R is calcium trioxocarbonate(IV), CaCO₃.
\(ZnCO_3 + H_2SO_4 \rightarrow ZnSO_4 + H_2O + CO_2\); \(CO_2 + Ca(OH)_2 \rightarrow CaCO_3 + H_2O\)

(b) Suitable apparatus, with a reason for each:

• Storage of dilute silver trioxonitrate(V): a dark (amber/brown) reagent bottle, because silver trioxonitrate(V) is light-sensitive and decomposes in bright light.
• Heating copper metal: a crucible (on a pipe-clay triangle), because it can withstand strong, direct heating.
• Separating water and kerosene: a separating funnel, because the two liquids are immiscible and settle into layers that can be run off separately.